The present invention relates to reciprocating internal combustion engines and, in particular, it concerns a compound engine composed of crankshaftless internal combustion units associated with an impulse turbine unit.
It has long been recognized in internal combustion engines that by increasing the compression ratio the thermodynamic efficiency of the combustion process rises. That is, from the thermodynamic point of view, higher specific output from internal combustion engines is possible through higher working pressure involving higher delivering temperatures. In the pursuit of higher power engines, excess load on the crankshaft, connecting rods, and the support bearing, and excessive supplementary torsional vibration, which cause crankshaft trouble, have became severe problems. Another drawback in the standard reciprocating internal combustion engines is an increased noise level produced by impacts of the pistons in a lateral direction against the walls of each cylinder due to transverse forces caused by the inclination of the connecting rods.
Several types of crankshaftless internal combustion engines have been suggested, most notable being the Wankel rotary engines. However, due to problems associated with the complexity of sealing of the combustion chamber and work space with the rotating rings, none of these engines resulted in a reliable, long life version.
Other suggestion of crankshaftless internal combustion engines include those disclosed in DE10124056 to Sperling, and U.S. Pat. No. 4,966,000 to Wolters. In both of these engines the fluid chamber is located between two pistons coupled to each other by a common rod, thus the working fluid is located close to combustion chamber. This will inevitably result in some working fluid getting past the piston rings and entering into the combustion chamber. Alternatively, gases from combustion chamber may blow by the piston rings and contaminate the working liquid, which may be overheated and irreversibly damaged.
In the Sperling device, there are no bladed guide devices at the input of the turbine. Working fluid from the fluid chamber is forced to the turbine through passages, which results in significant power losses.
There is therefore a need for a compound engine composed of a crankshaftless internal combustion units associated with an impulse turbine unit in which combustion chambers are separated from the fluid pumping mechanism and that the energy of the burning down fuel in the engine cylinders is transferred substantially directly to the hydraulic working liquid.